Efficient method for optimizing long-term retention backup policy within recovery point objectives (rpo)

ABSTRACT

An efficient method for optimizing long-term retention backup policy within recovery point objectives (RPO). Specifically, the disclosed method proposes a dynamic promotion scheme through which short-term retention backup copies, in compliance with specified long-term retention RPOs, may be promoted to render long-term retention backup copies. Further, the disclosed method not only looks to past and/or presently dated short-term retention backup copies, but also looks to prospective (or future) dated short-term retention backup copies, which are expected or predicted to be produced, for promotion. Moreover, in circumstances where there are no appropriate past, present, or future dated short-term retention backup copies to promote, the disclosed method triggers new backup operations to acquire the long-term retention backup copies necessary to maintain the specified long-retention RPOs.

BACKGROUND

In the realm of data protection, innumerable methods have been conceivedto produce long-term retention backup copies. One such method reliesupon the promotion of existing backup copies.

SUMMARY

In general, in one aspect, the invention relates to a method foroptimizing long-term retention backup policy. The method includesperforming a first search for a first current short-term retention assetcopy, computing a first forward duration based on the first searchresulting in the first current short-term retention asset copy not beingfound, obtaining, based on the first forward duration not exceeding afirst long-term retention recovery point objective (RPO), a first backupoperation prediction for a first next short-term retention backupoperation, and waiting, based on the first backup operation predictionforecasting that the first next short-term retention backup operation ismost likely to succeed, for a first next short-term retention timeinterval during which a first next short-term retention asset copy isexpected to be created through the first next short-term retentionbackup operation, wherein the first next short-term retention asset copyis subsequently expected to be promoted to obtain a first currentlong-term retention asset copy.

In general, in one aspect, the invention relates to a non-transitorycomputer readable medium (CRM). The non-transitory CRM includes computerreadable program code, which when executed by a computer processor,enables the computer processor to perform a method for optimizinglong-term retention backup policy. The method includes performing afirst search for a first current short-term retention asset copy,computing a first forward duration based on the first search resultingin the first current short-term retention asset copy not being found,obtaining, based on the first forward duration not exceeding a firstlong-term retention recovery point objective (RPO), a first backupoperation prediction for a first next short-term retention backupoperation, and waiting, based on the first backup operation predictionforecasting that the first next short-term retention backup operation ismost likely to succeed, for a first next short-term retention timeinterval during which a first next short-term retention asset copy isexpected to be created through the first next short-term retentionbackup operation, wherein the first next short-term retention asset copyis subsequently expected to be promoted to obtain a first currentlong-term retention asset copy.

In general, in one aspect, the invention relates to a system foroptimizing long-term retention backup policy. The system includes abackup storage system that includes a computer processor, and memorythat includes instructions, which when executed by the computerprocessor, enables the computer processor to perform a method. Themethod includes performing a search for a current short-term retentionasset copy, computing a forward duration based on the search resultingin the current short-term retention asset copy not being found,obtaining, based on the forward duration not exceeding a long-termretention recovery point objective (RPO), a backup operation predictionfor a next short-term retention backup operation, and waiting, based onthe backup operation prediction forecasting that the next short-termretention backup operation is most likely to succeed, for a nextshort-term retention time interval during which a next short-termretention asset copy is expected to be created through the nextshort-term retention backup operation, wherein the next short-termretention asset copy is subsequently expected to be promoted to obtain acurrent long-term retention asset copy.

Other aspects of the invention will be apparent from the followingdescription and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a system in accordance with one or more embodiments of theinvention.

FIGS. 2A and 2B show flowcharts describing a method for optimizinglong-term retention backup policy within a recovery point objective(RPO) in accordance with one or more embodiments of the invention.

FIG. 3 shows an exemplary computing system in accordance with one ormore embodiments of the invention.

FIGS. 4A-4C show exemplary scenarios in accordance with one or moreembodiments of the invention.

DETAILED DESCRIPTION

Specific embodiments of the invention will now be described in detailwith reference to the accompanying figures. In the following detaileddescription of the embodiments of the invention, numerous specificdetails are set forth in order to provide a more thorough understandingof the invention. However, it will be apparent to one of ordinary skillin the art that the invention may be practiced without these specificdetails. In other instances, well-known features have not been describedin detail to avoid unnecessarily complicating the description.

In the following description of FIGS. 1-4C, any component described withregard to a figure, in various embodiments of the invention, may beequivalent to one or more like-named components described with regard toany other figure. For brevity, descriptions of these components will notbe repeated with regard to each figure. Thus, each and every embodimentof the components of each figure is incorporated by reference andassumed to be optionally present within every other figure having one ormore like-named components. Additionally, in accordance with variousembodiments of the invention, any description of the components of afigure is to be interpreted as an optional embodiment which may beimplemented in addition to, in conjunction with, or in place of theembodiments described with regard to a corresponding like-namedcomponent in any other figure.

Throughout the application, ordinal numbers (e.g., first, second, third,etc.) may be used as an adjective for an element (i.e., any noun in theapplication). The use of ordinal numbers is not to necessarily imply orcreate any particular ordering of the elements nor to limit any elementto being only a single element unless expressly disclosed, such as bythe use of the terms “before”, “after”, “single”, and other suchterminology. Rather, the use of ordinal numbers is to distinguishbetween the elements. By way of an example, a first element is distinctfrom a second element, and a first element may encompass more than oneelement and succeed (or precede) the second element in an ordering ofelements.

In general, embodiments of the invention relate to an efficient methodfor optimizing long-term retention backup policy within recovery pointobjectives (RPO). Specifically, the disclosed method proposes a dynamicpromotion scheme through which short-term retention backup copies, incompliance with specified long-term retention RPOs, may be promoted torender long-term retention backup copies. Further, the disclosed methodnot only looks to past and/or presently dated short-term retentionbackup copies, but also looks to prospective (or future) datedshort-term retention backup copies, which are expected or predicted tobe produced, for promotion. Moreover, in circumstances where there areno appropriate past, present, or future dated short-term retentionbackup copies to promote, the disclosed method triggers new backupoperations to acquire the long-term retention backup copies necessary tomaintain the specified long-retention RPOs.

FIG. 1 shows a system in accordance with one or more embodiments of theinvention. The system (100) may include a client device (102) thatoperatively connects to a backup storage system (110). Each of thesesystem (100) components is described below.

In one embodiment of the invention, the above-mentioned system (100)components may operatively connect to one another through a network (notshown) (e.g., a local area network (LAN), a wide area network (WAN) suchas the Internet, a mobile network, any other network type, or anycombination thereof). The network may be implemented using anycombination of wired and/or wireless connections. Further, the networkmay encompass various interconnected, network-enabled subcomponents (orsystems) (e.g., switches, routers, gateways, etc.) that may facilitatecommunications between the above-mentioned system (100) components.Moreover, the above-mentioned system (100) components may communicatewith one another using any combination of wired and/or wirelesscommunication protocols.

In one embodiment of the invention, the client device (102) mayrepresent any physical appliance or computing system designed andconfigured to receive, generate, process, store, and/or transmit digitaldata, as well as to provide an environment in which one or more computerprograms may execute thereon. The computer programs (e.g., clientprotection agent (104) (described below)) may, for example, implementlarge-scale and complex data processing; or implement one or moreservices offered locally or over a network. Further, in providing anexecution environment for any computer programs installed thereon, theclient device (102) may include and allocate various resources (e.g.,computer processors, memory, storage, virtualization, network bandwidth,etc.), as needed, to the computer programs and the tasks (or processes)instantiated thereby. One of ordinary skill will appreciate that theclient device (102) may perform other functionalities without departingfrom the scope of the invention. Examples of the client device (102) mayinclude, but are not limited to, a desktop computer, a laptop computer,a server, a mainframe, or any other computing system similar to theexemplary computing system shown in FIG. 3. Moreover, the client device(102) may include, but is not limited to, a client protection agent(104) and a client asset (106). Each of these client device (102)subcomponents is described below.

In one embodiment of the invention, the client protection agent (104)may refer to a computer program that may execute on the underlyinghardware of the client device (102). Specifically, the client protectionagent (104) may be configured to perform client-side asset backup andrecovery operations. To that extent, the client protection agent (104)may protect one or more client assets (e.g., client asset (106)) on theclient device (102) against data loss (i.e., backup the asset(s)); andreconstruct one or more assets on the client device (102) following suchdata loss (i.e., recover the asset(s)). One of ordinary skill willappreciate that the client protection agent (104) may perform otherfunctionalities without departing from the scope of the invention.

In one embodiment of the invention, the client asset (106) may refer toa database, or any logical container to and from which data (or anygranularity thereof), which has been received by or generated on theclient device (102), may be stored and retrieved, respectively. Theclient asset (106) may occupy any portion of persistent storage (notshown) available on the client device (102). Examples of persistentstorage may include, but are not limited to, optical storage, magneticstorage, NAND Flash Memory, NOR Flash Memory, Magnetic Random AccessMemory (M-RAM), Spin Torque Magnetic RAM (ST-MRAM), Phase Change Memory(PCM), or any other storage defined as non-volatile Storage Class Memory(SCM).

In one embodiment of the invention, the backup storage system (110) mayrepresent any data backup, archiving, and/or disaster recovery storageservice. The backup storage system (110) may be implemented using one ormore servers (not shown). Each server may encompass a physical orvirtual server, which may reside in an on-premises data center, a cloudcomputing environment, or a hybrid infrastructure thereof. Additionally,or alternatively, the backup storage system (110) may be implementedusing one or more computing systems similar to the exemplary computingsystem shown in FIG. 3. Furthermore, the backup storage system (110) mayinclude, but is not limited to, a backup operation predictor (112), abackup protection agent (114), and an asset copy repository (116). Eachof these backup storage system (110) subcomponents is described below.

In one embodiment of the invention, the backup operation predictor (112)may refer to a computer program that may execute on the underlyinghardware of the backup storage system (110). Specifically, the backupoperation predictor (112) may be configured to forecast the success orfailure of future short-term retention backup operations. To thatextent, the backup operation predictor (112) may include functionalityto: obtain forecast request(s) from the backup protection agent (114),which may pertain to predicting whether a future short-term retentionbackup operation (e.g., targeting the client asset (106) on the clientdevice (102)) is most likely to result in success or failure; based onthe obtained forecast request(s), derive backup operation prediction(s)entailing future short-term retention backup(s) (described below); andprovide the derived backup operation prediction(s) to the backupprotection agent (114) in response to the obtained forecast request(s).One of ordinary skill will appreciate that the backup operationpredictor (112) may perform other functionalities without departing fromthe scope of the invention.

In one embodiment of the invention, any backup operation predictions maybe derived from analyses applied to select information. Theaforementioned select information may include, but is not limited to:backup error and/or exception logs maintained on the backup storagesystem (110) for one or more attempted, yet failed, past (and present)short-term backup operations; a state and utilization history associatedwith the backup targeted asset(s) (e.g., client asset (106)) on theclient device (102); and any other information descriptive of backupfailures and/or the backup targeted asset(s). The aforementioned selectinformation is not limited to the aforementioned examples. Further, theanalyses applied thereto may include any existing pattern-findingalgorithms, including, but not limited to, algorithms implementedthrough artificial intelligence and/or machine learning.

In one embodiment of the invention, the backup protection agent (114)may refer to a computer program that may execute on the underlyinghardware of the backup storage system (110). Specifically, the backupprotection agent (114) may be configured to perform server-side assetbackup and recovery operations. To that extent, in general, the backupprotection agent (114) may receive asset data, submitted by the clientdevice (102), to store in the asset copy repository (116) during assetbackup operations; and, conversely, may retrieve asset data from theasset copy repository (116) during asset recovery operations. Further,at least concerning embodiments of the invention, the backup protectionagent (114) may include functionality to perform the method outlined inFIGS. 2A and 2B, below, which is directed to optimizing long-termretention backup policy within a recovery point objective (RPO). One ofordinary skill will appreciate that the backup protection agent (114)may perform other functionalities without departing from the scope ofthe invention.

In one embodiment of the invention, the asset copy repository (116) mayrefer to physical storage (or logical storage occupying at least aportion of the physical storage) on the backup storage system (110),where short-term retention asset copies (not shown) and long-termretention asset copies (not shown) (of at least the client asset (106)of the client device (102)) may be consolidated. The asset copyrepository (116) may, at least in part, include persistent storage.Examples of persistent storage may include, but are not limited to,optical storage, magnetic storage, NAND Flash Memory, NOR Flash Memory,Magnetic Random Access Memory (M-RAM), Spin Torque Magnetic RAM(ST-MRAM), Phase Change Memory (PCM), or any other storage defined asnon-volatile Storage Class Memory (SCM).

While FIG. 1 shows a configuration of components, other system (100)configurations may be used without departing from the scope of theinvention. For example, the system (100) may further include one or moreadditional client devices (not shown) and/or one or more additionalbackup storage systems (not shown). By way of another example, theclient device (102) may further include one or more additional clientassets (not shown).

FIGS. 2A and 2B show flowcharts describing a method for optimizinglong-term retention backup policy within a recovery point objective(RPO) in accordance with one or more embodiments of the invention. Thevarious steps outlined below may be performed by a backup protectionagent of a backup storage system (see e.g., FIG. 1). Further, while thevarious steps in the flowcharts are presented and describedsequentially, one of ordinary skill will appreciate that some or allsteps may be executed in different orders, may be combined or omitted,and some or all steps may be executed in parallel.

Turning to FIG. 2A, in Step 200, a short-term retention backup operationis attempted. In one embodiment of the invention, the short-termretention backup operation may reference a scheduled process directed toasset replication, which may trigger at the periodic onset of aspecified short-term retention time interval (e.g., one or more days).Further, the short-term retention backup operation may target a clientasset (or any changes therein differing from a last short-term retentionasset copy thereof) on a client device. Hereinafter, if the short-termretention backup operation was successful, the method proceeds to Step202; otherwise, if the short-term retention backup operation was afailure, the method alternatively proceeds to Step 204.

In Step 202, following the success of the short-term retention backupoperation (attempted in Step 200), a short-term retention asset copyresulting therefrom is stored in an asset copy repository (see e.g.,FIG. 1) of the backup storage system. In one embodiment of theinvention, the short-term retention asset copy (also referred to as acurrent short-term retention asset copy) may refer to a replication ofthe client asset (or any changes therein differing from a lastshort-term retention asset copy thereof) that had been obtained at acurrent short-term retention time interval (which may coincide with acurrent date).

In Step 204, following the failure of the short-term retention backupoperation (attempted in Step 200), or following the storage of a(current) short-term retention asset copy (in Step 202), a determinationis made as to whether a long-term retention backup operation has beentriggered. The long-term retention backup operation may reference ascheduled process directed to asset replication, which may trigger atthe periodic onset of a specified long-term retention time interval(e.g., one or more weeks, one or more months, one or more years).Further, similar to the short-term retention backup operation, along-term retention backup operation may also target the client asset(or any changes therein differing from a last short-term retention assetcopy thereof) on a client device. Accordingly, in one embodiment of theinvention, if it is determined that the specified long-term retentiontime interval has not elapsed, then the long-term retention backupoperation has not triggered and the method proceeds to Step 206. On theother hand, in another embodiment of the invention, if it isalternatively determined that the specified long-term retention timeinterval has elapsed, then the long-term retention backup operation hastriggered and the method alternatively proceeds to Step 208.

In Step 206, following the determination (in Step 204) that a long-termretention backup operation has not triggered, the periodic onset of anext short-term retention time interval is waited on. Thereafter, uponthe occurrence of the periodic onset of the next short-term retentiontime interval, the method proceeds to Step 200, where another short-termretention backup operation may be attempted.

In Step 208, following the alternative determination (in Step 204) thata long-term retention backup operation has triggered, a search for acurrent short-term retention asset copy (described above) is performed.In one embodiment of the invention, the search may be conductedthroughout an asset copy repository (see e.g., FIG. 1) on the backupstorage system, and may entail examining creation timestamps associatedwith short-term retention asset copies, of the client asset, for ashort-term retention asset copy (if any) created on a current date.

In Step 210, a determination is made as to whether the search (performedin Step 208) resulted in a current short-term retention asset copy beingfound. Accordingly, in one embodiment of the invention, if it isdetermined that a current short-term retention asset copy has beenfound, then the method proceeds to Step 212. On the other hand, inanother embodiment of the invention, if it is determined that a currentshort-term retention asset copy has not been found, then the methodalternatively proceeds to Step 214.

In Step 212, following the determination (in Step 210) that a currentshort-term retention asset copy has been found, the current short-termretention asset copy is promoted. That is, in one embodiment of theinvention, the long-term retention backup operation (triggered in Step204) may entail the creation of a current long-term retention asset copythrough duplication of the current short-term retention asset copy—e.g.,a duplicate of the current short-term retention asset copy becomes thecurrent long-term retention asset copy. The current long-term retentionasset copy may refer to a replication of the client asset (or anychanges therein differing from a last long-term retention asset copythereof) that had been obtained at a current long-term retention timeinterval (which may coincide with a current date). The current long-termretention asset copy may subsequently be stored in the asset copyrepository on the backup storage system. Hereinafter, the methodproceeds to Step 206, where the periodic onset of a next short-termretention time interval may be waited on.

In Step 214, following the alternative determination (in Step 210) thata current short-term retention asset copy has not been found, a forwardduration is computed. In one embodiment of the invention, the forwardduration may encompass a length of time between an expected timestampreflecting the onset of a next short-term retention time interval (e.g.,the onset of a next day) and a recorded timestamp reflecting thecreation date of a last long-term retention asset copy. The lastlong-term retention asset copy may refer to a long-term retention assetcopy that had been created as a result of the triggering of a lastlong-term retention backup operation—i.e., a long-term retention backupoperation that transpired at a given past point-in-time that is mostchronologically proximal to a current time. Hereinafter, the methodproceeds to Step 220 (see e.g., FIG. 2B).

Turning to FIG. 2B, in Step 220, a determination is made as to whetherthe forward duration (computed in Step 214) does not exceed (i.e., isless than or equal to) a specified long-term retention recovery pointobjective (RPO). A long-term retention RPO may refer to a maximum lengthof time, in compliance with an established service level agreement(SLA), permitted between the creation and storage of consecutivelong-term retention asset copies. Accordingly, in one embodiment of theinvention, if it is determined that the forward duration does not exceedthe specified long-term retention recovery RPO, then the method proceedsto Step 222. On the other hand, in another embodiment of the invention,if it is alternatively determined that the forward duration does exceedthe specified long-term retention RPO, then the method alternativelyproceeds to Step 226.

In Step 222, following the determination (in Step 220) that the forwardduration (computed in Step 214) does not exceed the specified long-termretention RPO, a backup operation prediction is obtained. In oneembodiment of the invention, the backup operation prediction mayencompass a forecast reflecting whether a next (future) short-termretention backup operation (e.g., to be attempted at the onset of a next(future) short-term retention time interval) would be a success or afailure. Further, the backup operation prediction may be obtained fromthe backup operation predictor (see e.g., FIG. 1) on the backup storagesystem.

In Step 224, a determination is made as to whether the backup operationprediction (obtained in Step 222) forecasts that a next (future)short-term retention backup operation will most likely fail.Accordingly, in one embodiment of the invention, if it is determinedthat the next (future) short-term retention backup operation is mostlikely to fail, then the method proceeds to Step 226. On the other hand,in another embodiment of the invention, if it is alternativelydetermined that the next (future) short-term retention backup operationis most likely to succeed, then the method alternatively proceeds toStep 206 (see e.g., FIG. 2A), where the periodic onset of the next(future) short-term retention time interval may be waited on.

In Step 226, following the determination (in Step 224) that the backupoperation prediction (obtained in Step 222) forecasts that a next(future) short-term retention backup operation will most likely fail, abackward duration is computed. In one embodiment of the invention, thebackward duration may encompass a length of time between an expectedtimestamp reflecting the onset of a next long-term retention timeinterval (e.g., the onset of a next week/month/year) and a recordedtimestamp reflecting the creation date of a last short-term retentionasset copy. The last short-term retention asset copy may refer to ashort-term retention asset copy that had been successfully created as aresult of the triggering of a last short-term retention backupoperation—i.e., a short-term retention backup operation thatsuccessfully completed at a given past point-in-time that is mostchronologically proximal to a current time.

In Step 228, a determination is made as to whether the backward duration(computed in Step 226) does not exceed (i.e., is less than or equal to)the specified long-term retention RPO (described above). Accordingly, inone embodiment of the invention, if it is determined that the backwardduration does not exceed the specified long-term retention recovery RPO,then the method proceeds to Step 230. On the other hand, in anotherembodiment of the invention, if it is alternatively determined that thebackward duration does exceed the specified long-term retention RPO,then the method alternatively proceeds to Step 232.

In Step 230, following the determination (in Step 228) that the backwardduration (computed in Step 226) does not exceed the specified long-termretention RPO, the above-mentioned last short-term retention asset copyis promoted. That is, in one embodiment of the invention, the long-termretention backup operation (triggered in Step 204) may entail thecreation of a current long-term retention asset copy through duplicationof the last short-term retention asset copy—e.g., a duplicate of thelast short-term retention asset copy becomes the current long-termretention asset copy. The current long-term retention asset copy maysubsequently be stored in the asset copy repository on the backupstorage system. Hereinafter, the method proceeds to Step 206 (see e.g.,FIG. 2A), where the periodic onset of a next (future) short-termretention time interval may be waited on.

In Step 232, following the alternative determination (in Step 228) thatthe backward duration (computed in Step 226) does exceed the specifiedlong-term retention RPO, a long-term retention backup operation,entailing the direct replication of the client asset (or any changestherein differing from a last long-term retention asset copy thereof) ona client device, is initiated. In one embodiment of the invention,initiation and completion of the aforementioned long-term retentionbackup operation may result in obtaining a current long-term retentionasset copy.

In Step 234, the current long-term retention asset copy (obtained inStep 232) is subsequently stored in the asset copy repository (see e.g.,FIG. 1) on the backup storage system. Hereinafter, the method proceedsto Step 206 (see e.g., FIG. 2A), where the periodic onset of a next(future) short-term retention time interval may be waited on.

FIG. 3 shows an exemplary computing system in accordance with one ormore embodiments of the invention. The computing system (300) mayinclude one or more computer processors (302), non-persistent storage(304) (e.g., volatile memory, such as random access memory (RAM), cachememory), persistent storage (306) (e.g., a hard disk, an optical drivesuch as a compact disk (CD) drive or digital versatile disk (DVD) drive,a flash memory, etc.), a communication interface (312) (e.g., Bluetoothinterface, infrared interface, network interface, optical interface,etc.), input devices (310), output devices (308), and numerous otherelements (not shown) and functionalities. Each of these components isdescribed below.

In one embodiment of the invention, the computer processor(s) (302) maybe an integrated circuit for processing instructions. For example, thecomputer processor(s) may be one or more cores or micro-cores of acentral processing unit (CPU) and/or a graphics processing unit (GPU).The computing system (300) may also include one or more input devices(310), such as a touchscreen, keyboard, mouse, microphone, touchpad,electronic pen, or any other type of input device. Further, thecommunication interface (312) may include an integrated circuit forconnecting the computing system (300) to a network (not shown) (e.g., alocal area network (LAN), a wide area network (WAN) such as theInternet, mobile network, or any other type of network) and/or toanother device, such as another computing device.

In one embodiment of the invention, the computing system (300) mayinclude one or more output devices (308), such as a screen (e.g., aliquid crystal display (LCD), a plasma display, touchscreen, cathode raytube (CRT) monitor, projector, or other display device), a printer,external storage, or any other output device. One or more of the outputdevices may be the same or different from the input device(s). The inputand output device(s) may be locally or remotely connected to thecomputer processor(s) (302), non-persistent storage (304), andpersistent storage (306). Many different types of computing systemsexist, and the aforementioned input and output device(s) may take otherforms.

Software instructions in the form of computer readable program code toperform embodiments of the invention may be stored, in whole or in part,temporarily or permanently, on a non-transitory computer readable mediumsuch as a CD, DVD, storage device, a diskette, a tape, flash memory,physical memory, or any other computer readable storage medium.Specifically, the software instructions may correspond to computerreadable program code that, when executed by a processor(s), isconfigured to perform one or more embodiments of the invention.

FIGS. 4A-4C show exemplary scenarios in accordance with one or moreembodiments of the invention. The exemplary scenarios, illustratedthrough FIGS. 4A-4C and described below, are for explanatory purposesonly and not intended to limit the scope of the invention.

For each of the following exemplary scenarios, consider an asset backuppolicy characterized through: (a) a short-term retention time intervalof one day, meaning an attempt is to be made daily to obtain ashort-term retention asset copy; (b) a long-term retention time intervalof one week, meaning a long-term retention asset copy is to be obtainedweekly (e.g., on every Sunday); and (c) a long-term retention recoverypoint objective (RPO) of eight days, meaning a maximum of eight days ispermitted to elapse between consecutive creations of long-term retentionasset copies.

Exemplary Scenario 1 (FIG. 4A)

-   -   1. On Sunday, an attempt to produce a Sunday short-term asset        copy succeeds. Also, because it is Sunday, a long-term retention        backup operation is triggered. Because the Sunday short-term        asset copy exists, it is promoted to obtain a Sunday long-term        retention asset copy.    -   2. From Monday through Saturday, attempts to produce Monday        through Saturday short-term asset copies, respectively, all        succeed. Also, throughout the aforementioned days, long-term        retention backup operation(s) do not trigger because each of        these aforementioned days is not a Sunday.    -   3. On Sunday′, an attempt to produce a Sunday′ (current)        short-term asset copy fails. Also, because it is Sunday′, a        long-term retention backup operation is triggered.    -   4. Because a Sunday′ short-term asset copy does not exist, a        forward duration is computed (i.e., 8 days), which reflects the        length of time between a next (future) short-term retention time        interval (i.e., Monday′) and the date of a last long-term        retention asset copy (i.e., Sunday). The forward duration does        not exceed the specified long-term retention RPO (i.e., 8 days)        and, accordingly, a backup operation prediction is obtained for        a short-term retention backup operation that is expected to take        place on Monday′.    -   5. The backup operation prediction forecasts that the short-term        retention backup operation that is expected to take place on        Monday′ will most likely succeed. Based on this forecast, the        Sunday′ (current) long-term retention asset copy will be        obtained from the promotion of a Monday′ short-term retention        asset copy that is expected to be produced the next day.

Exemplary Scenario 2 (FIG. 4B)

-   -   1. On Sunday, an attempt to produce a Sunday short-term asset        copy succeeds. Also, because it is Sunday, a long-term retention        backup operation is triggered. Because the Sunday short-term        asset copy exists, it is promoted to obtain a Sunday long-term        retention asset copy.    -   2. From Monday through Saturday, attempts to produce Monday        through Saturday short-term asset copies, respectively, all        succeed. Also, throughout the aforementioned days, long-term        retention backup operation(s) do not trigger because each of        these aforementioned days is not a Sunday.    -   3. On Sunday′, an attempt to produce a Sunday′ (current)        short-term asset copy fails. Also, because it is Sunday′, a        long-term retention backup operation is triggered.    -   4. Because a Sunday′ short-term asset copy does not exist, a        forward duration is computed (i.e., 8 days), which reflects the        length of time between a next (future) short-term retention time        interval (i.e., Monday′) and the date of a last long-term        retention asset copy (i.e., Sunday). The forward duration does        not exceed the specified long-term retention RPO (i.e., 8 days)        and, accordingly, a backup operation prediction is obtained for        a short-term retention backup operation that is expected to take        place on Monday′. The backup operation prediction, however,        forecasts that that the short-term retention backup operation        that is expected to take place on Monday′ will most likely fail.    -   5. Based on the backup operation prediction, a second forward        duration is computed (i.e., 9 days), which reflects the length        of time between a second next (future) short-term retention time        interval (i.e., Tuesday′) and the date of the last long-term        retention asset copy (i.e., Sunday).    -   6. The second forward duration exceeds the specified long-term        retention RPO (i.e., 8 days) and, accordingly, a backward        duration is computed (i.e., 8 days), which reflects the length        of time between a date of a last short-term retention asset copy        (i.e., Saturday) and a next (future) long-term retention time        interval (i.e., Sunday″).    -   7. The backward duration does not exceed the specified long-term        retention RPO (i.e., 8 days) and, accordingly, the Saturday        short-term retention asset copy is promoted to obtain the        Sunday′ (current) long-term retention asset copy.

Exemplary Scenario 3 (FIG. 4C)

-   -   1. On Sunday, an attempt to produce a Sunday short-term asset        copy succeeds. Also, because it is Sunday, a long-term retention        backup operation is triggered. Because the Sunday short-term        asset copy exists, it is promoted to obtain a Sunday long-term        retention asset copy.    -   2. From Monday through Friday, attempts to produce Monday        through Friday short-term asset copies, respectively, all        succeed. On Saturday, however, an attempt to produce a Saturday        short-term retention asset copy fails. Also, throughout the        aforementioned days, long-term retention backup operation(s) do        not trigger because each of these aforementioned days is not a        Sunday.    -   3. On Sunday′, an attempt to produce a Sunday′ (current)        short-term asset copy fails. Also, because it is Sunday′, a        long-term retention backup operation is triggered.    -   4. Because a Sunday′ short-term asset copy does not exist, a        forward duration is computed (i.e., 8 days), which reflects the        length of time between a next (future) short-term retention time        interval (i.e., Monday′) and the date of a last long-term        retention asset copy (i.e., Sunday). The forward duration does        not exceed the specified long-term retention RPO (i.e., 8 days)        and, accordingly, a backup operation prediction is obtained for        a short-term retention backup operation that is expected to take        place on Monday′. The backup operation prediction, however,        forecasts that that the short-term retention backup operation        that is expected to take place on Monday′ will most likely fail.    -   5. Based on the backup operation prediction, a second forward        duration is computed (i.e., 9 days), which reflects the length        of time between a second next (future) short-term retention time        interval (i.e., Tuesday′) and the date of the last long-term        retention asset copy (i.e., Sunday).    -   6. The second forward duration exceeds the specified long-term        retention RPO (i.e., 8 days) and, accordingly, a backward        duration is computed (i.e., 9 days), which reflects the length        of time between a date of a last short-term retention asset copy        (i.e., Friday) and a next (future) long-term retention time        interval (i.e., Sunday″).    -   7. The backward duration exceeds the specified long-term        retention RPO (i.e., 8 days) and, accordingly, a new long-term        retention asset copy is produced, thereby becoming the Sunday′        (current) long-term retention asset copy.

While the invention has been described with respect to a limited numberof embodiments, those skilled in the art, having benefit of thisdisclosure, will appreciate that other embodiments can be devised whichdo not depart from the scope of the invention as disclosed herein.Accordingly, the scope of the invention should be limited only by theattached claims.

What is claimed is:
 1. A method for optimizing long-term retentionbackup policy, the method comprising: performing a first search for afirst current short-term retention asset copy; computing a first forwardduration based on the first search resulting in the first currentshort-term retention asset copy not being found; obtaining, based on thefirst forward duration not exceeding a first long-term retentionrecovery point objective (RPO), a first backup operation prediction fora first next short-term retention backup operation; and waiting, basedon the first backup operation prediction forecasting that the first nextshort-term retention backup operation is most likely to succeed, for afirst next short-term retention time interval during which a first nextshort-term retention asset copy is expected to be created through thefirst next short-term retention backup operation, wherein the first nextshort-term retention asset copy is subsequently expected to be promotedto obtain a first current long-term retention asset copy.
 2. The methodof claim 1, wherein the first forward duration reflects a length of timebetween an expected timestamp for the first next-short term retentiontime interval and a recorded timestamp for a last long-term retentionasset copy.
 3. The method of claim 1, wherein the first long-termretention RPO defines a maximum length of time permitted to elapsebetween creations of consecutive long-term retention asset copies. 4.The method of claim 1, the method further comprising: performing asecond search for a second current short-term retention asset copy; andpromoting, based on the second search resulting in the second currentshort-term retention asset copy being found, the second currentshort-term retention asset copy to obtain a second current long-termretention asset copy.
 5. The method of claim 1, the method furthercomprising: performing a second search for a second current short-termretention asset copy; computing a second forward duration based on thesecond search resulting in the second current short-term retention assetcopy not being found; obtaining, based on the second forward durationnot exceeding a second long-term retention RPO, a second backupoperation prediction for a second next short-term retention backupoperation; computing a backward duration based on the second backupoperation prediction forecasting that the second next short-termretention backup operation is most likely to fail; and promoting, basedon the backward duration not exceeding the second long-term retentionRPO, a last short-term retention asset copy to obtain a second currentlong-term retention asset copy.
 6. The method of claim 5, wherein thebackward duration reflects a length of time between an expectedtimestamp for a next long-term retention time interval and a recordedtimestamp for the last short-term retention asset copy.
 7. The method ofclaim 1, the method further comprising: performing a second search for asecond current short-term retention asset copy; computing a secondforward duration based on the second search resulting in the secondcurrent short-term retention asset copy not being found; obtaining,based on the second forward duration not exceeding a second long-termretention RPO, a second backup operation prediction for a second nextshort-term retention backup operation; computing a backward durationbased on the second backup operation prediction forecasting that thesecond next short-term retention backup operation is most likely tofail; and initiating, based on the backward duration exceeding thesecond long-term retention RPO, a long-term retention backup operationto obtain a second current long-term retention asset copy.
 8. The methodof claim 1, the method further comprising: performing a second searchfor a second current short-term retention asset copy; computing a secondforward duration based on the second search resulting in the secondcurrent short-term retention asset copy not being found; computing abackward duration based on the second forward duration exceeding asecond long-term retention RPO; and promoting, based on the backwardduration not exceeding the second long-term retention RPO, a lastshort-term retention asset copy to obtain a second current long-termretention asset copy.
 9. The method of claim 1, the method furthercomprising: performing a second search for a second current short-termretention asset copy; computing a second forward duration based on thesecond search resulting in the second current short-term retention assetcopy not being found; computing a backward duration based on the secondforward duration exceeding a second long-term retention RPO; andinitiating, based on the backward duration exceeding the secondlong-term retention RPO, a long-term retention backup operation toobtain a second current long-term retention asset copy.
 10. Anon-transitory computer readable medium (CRM) comprising computerreadable program code, which when executed by a computer processor,enables the computer processor to perform a method for optimizinglong-term retention backup policy, the method comprising: performing afirst search for a first current short-term retention asset copy;computing a first forward duration based on the first search resultingin the first current short-term retention asset copy not being found;obtaining, based on the first forward duration not exceeding a firstlong-term retention recovery point objective (RPO), a first backupoperation prediction for a first next short-term retention backupoperation; and waiting, based on the first backup operation predictionforecasting that the first next short-term retention backup operation ismost likely to succeed, for a first next short-term retention timeinterval during which a first next short-term retention asset copy isexpected to be created through the first next short-term retentionbackup operation, wherein the first next short-term retention asset copyis subsequently expected to be promoted to obtain a first currentlong-term retention asset copy.
 11. The non-transitory CRM of claim 10,wherein the first forward duration reflects a length of time between anexpected timestamp for the first next-short term retention time intervaland a recorded timestamp for a last long-term retention asset copy. 12.The non-transitory CRM of claim 10, wherein the first long-termretention RPO defines a maximum length of time permitted to elapsebetween creations of consecutive long-term retention asset copies. 13.The non-transitory CRM of claim 10, wherein the method furthercomprises: performing a second search for a second current short-termretention asset copy; and promoting, based on the second searchresulting in the second current short-term retention asset copy beingfound, the second current short-term retention asset copy to obtain asecond current long-term retention asset copy.
 14. The non-transitoryCRM of claim 10, wherein the method further comprises: performing asecond search for a second current short-term retention asset copy;computing a second forward duration based on the second search resultingin the second current short-term retention asset copy not being found;obtaining, based on the second forward duration not exceeding a secondlong-term retention RPO, a second backup operation prediction for asecond next short-term retention backup operation; computing a backwardduration based on the second backup operation prediction forecastingthat the second next short-term retention backup operation is mostlikely to fail; and promoting, based on the backward duration notexceeding the second long-term retention RPO, a last short-termretention asset copy to obtain a second current long-term retentionasset copy.
 15. The non-transitory CRM of claim 14, wherein the backwardduration reflects a length of time between an expected timestamp for anext long-term retention time interval and a recorded timestamp for thelast short-term retention asset copy.
 16. The non-transitory CRM ofclaim 10, wherein the method further comprises: performing a secondsearch for a second current short-term retention asset copy; computing asecond forward duration based on the second search resulting in thesecond current short-term retention asset copy not being found;obtaining, based on the second forward duration not exceeding a secondlong-term retention RPO, a second backup operation prediction for asecond next short-term retention backup operation; computing a backwardduration based on the second backup operation prediction forecastingthat the second next short-term retention backup operation is mostlikely to fail; and initiating, based on the backward duration exceedingthe second long-term retention RPO, a long-term retention backupoperation to obtain a second current long-term retention asset copy. 17.The non-transitory CRM of claim 10, wherein the method furthercomprises: performing a second search for a second current short-termretention asset copy; computing a second forward duration based on thesecond search resulting in the second current short-term retention assetcopy not being found; computing a backward duration based on the secondforward duration exceeding a second long-term retention RPO; andpromoting, based on the backward duration not exceeding the secondlong-term retention RPO, a last short-term retention asset copy toobtain a second current long-term retention asset copy.
 18. Thenon-transitory CRM of claim 10, wherein the method further comprises:performing a second search for a second current short-term retentionasset copy; computing a second forward duration based on the secondsearch resulting in the second current short-term retention asset copynot being found; computing a backward duration based on the secondforward duration exceeding a second long-term retention RPO; andinitiating, based on the backward duration exceeding the secondlong-term retention RPO, a long-term retention backup operation toobtain a second current long-term retention asset copy.
 19. A system foroptimizing long-term retention backup policy, the system comprising: abackup storage system, comprising: a computer processor; and memorycomprising instructions, which when executed by the computer processor,enables the computer processor to perform a method, the methodcomprising: performing a search for a current short-term retention assetcopy; computing a forward duration based on the search resulting in thecurrent short-term retention asset copy not being found; obtaining,based on the forward duration not exceeding a long-term retentionrecovery point objective (RPO), a backup operation prediction for a nextshort-term retention backup operation; and waiting, based on the backupoperation prediction forecasting that the next short-term retentionbackup operation is most likely to succeed, for a next short-termretention time interval during which a next short-term retention assetcopy is expected to be created through the next short-term retentionbackup operation, wherein the next short-term retention asset copy issubsequently expected to be promoted to obtain a current long-termretention asset copy.
 20. The system of claim 19, the system furthercomprising: a client device operatively connected to the backup storagesystem and comprising a client asset, wherein the next short-termretention backup operation is expected to target the client asset.